Seat frame for vehicle

ABSTRACT

Right and left brackets coupling a seat back frame and seat cushion frame together are configured to adjust an amount of deformation upon impact absorption. A vehicle seat frame includes a seat cushion frame, seat back frame, coupling bracket configured to couple a cushion side frame as a side frame of the seat cushion frame on one side of the vehicle seat frame and a seat back side frame as a side frame of the seat back frame on the one side, and coupling bracket configured to couple a cushion side frame as a side frame of the seat cushion frame on the other side and a seat back side frame as a side frame of the seat back frame on the other side. Deformability upon impact absorption is different between a weak portion provided at the coupling bracket and a weak portion provided at the coupling bracket.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a National Stage Entry application of PCTApplication No. PCT/JP2016/072598, filed Aug. 2, 2016, which claims thepriority benefit of Japanese Patent Application No. JP 2015-154472,filed Aug. 4, 2015, the contents being incorporated herein by reference.

BACKGROUND

The present disclosure relates to a vehicle seat frame, and particularlyrelates to a vehicle seat frame configured such that a frame deformationamount upon a rear collision is adjustable.

There is a mechanism configured to enhance safety of a passenger byimpact absorption of a vehicle seat frame upon rear collision. Forexample, in a vehicle seat frame described in Patent ApplicationPublication WO 2013/133245 described below, a bracket configured tocouple a seat back frame and a seat cushion frame has a weak portion,and upon rear collision, impact is absorbed by deformation of the weakportion.

However, particularly in the case where components attached to right andleft frames of the seat cushion frame as a framework of a seatingportion are different from each other, load on the bracket is differentbetween the right and left brackets coupling the seat back frame and theseat cushion frame. For this reason, the right and left brackets mightnot deform equally upon rear collision.

SUMMARY

The present disclosure has been made in view of the above-describedproblem, and provides an embodiment of a vehicle seat frame configuredsuch that deformation amounts of right and left brackets upon impactabsorption are adjustable, the right and left brackets coupling a seatback frame and a seat cushion frame.

The above-described problem is solved by an embodiment of a vehicle seatframe including a seat cushion frame, a seat back frame, a firstcoupling bracket configured to couple a first cushion side frame as aside frame of the seat cushion frame on one side of the vehicle seatframe and a first seat back side frame as a side frame of the seat backframe on the one side, and a second coupling bracket configured tocouple a second cushion side frame as a side frame of the seat cushionframe on another side of the vehicle seat frame and a second seat backside frame as a side frame of the seat back frame on the other side.Deformability upon impact absorption is different between a first weakportion provided at the first coupling bracket and a second weak portionprovided at the second coupling bracket.

In the above-described vehicle seat frame, the deformability between theweak portions of the right and left coupling brackets coupling the seatcushion frame and the seat back frame is differentiated, and therefore,the amount of deformation of each of the right and left couplingbrackets upon impact absorption can be adjusted.

In the above-described vehicle seat frame, the first weak portion andthe second weak portion may be different from each other in theirrespective shapes. With this configuration, the amount of deformation ofeach of the right and left coupling brackets upon impact absorption canbe adjusted according to the shapes of the first and second weakportions.

In the above-described vehicle seat frame, the first coupling bracketmay include a first seat-back-side coupling region having a portion tobe coupled to the first seat back side frame, a first cushion-sidecoupling region having a portion to be coupled to the first cushion sideframe, and the first weak portion, the first weak portion connecting thefirst seat-back-side coupling region and the first cushion-side couplingregion together and being bent outward from the vehicle seat frame withrespect to the first seat-back-side coupling region and the firstcushion-side coupling region, and the second coupling bracket mayinclude a second seat-back-side coupling region having a portion to becoupled to the second seat back side frame, a second cushion-sidecoupling region having a portion to be coupled to the second cushionside frame, and the second weak portion, the second weak portionconnecting the second seat-back-side coupling region and the secondcushion-side coupling region together and being bent outward from thevehicle seat frame with respect to the second seat-back-side couplingregion and the second cushion-side coupling region. With thisconfiguration, each of the weak portions of the right and left couplingbrackets is bent outward from the vehicle seat frame upon impactabsorption so that impact on the seat back frame can be reduced.

In the above-described vehicle seat frame, an offset amount in a seatwidth direction between a surface forming the first seat-back-sidecoupling region and a surface forming the first cushion-side couplingregion at the first coupling bracket may be different from an offsetamount in the seat width direction between a surface forming the secondseat-back-side coupling region and a surface forming the secondcushion-side coupling region at the second coupling bracket. With thisconfiguration, the offset amount of each of the first and second weakportions is adjusted so that the deformability of each weak portion canbe controlled.

In the above-described vehicle seat frame, the surface forming the firstseat-back-side coupling region and the surface forming the firstcushion-side coupling region may be positioned within a same plane, andthe surface forming the second cushion-side coupling region may bepositioned inward or outward from the vehicle seat frame with respect tothe surface forming the second seat-back-side coupling region. With thisconfiguration, the second weak portion provided at the second couplingbracket can be more easily deformable upon impact absorption as comparedto the first weak portion provided at the first coupling bracket.

In the above-described vehicle seat frame, the second weak portion maybe formed to be more easily deformable upon impact absorption ascompared to the first weak portion. With this configuration, in a casewhere a stronger load is applied to the first coupling bracket than tothe second coupling bracket upon a rear collision, a balance in thedeformation amount between the second coupling bracket and the firstcoupling bracket can be achieved.

In the above-described vehicle seat frame, a main driving portion of aheight adjustment mechanism configured to adjust the height of the seatmay be provided only at the first cushion side frame of the first andsecond cushion side frames. With this configuration, the second couplingbracket to which a load of the main driving portion of the heightadjustment mechanism is not applied is more easily deformable than thefirst coupling bracket to which the load of the main driving portion ofthe height adjustment mechanism is applied, and therefore, the firstcoupling bracket and the second coupling bracket upon impact absorptioncan be deformed with a favorable balance.

In the above-described vehicle seat frame, a seating sensor mechanismconfigured to detect seating of a passenger may be provided only at thefirst cushion side frame of the first and second cushion side frames.With this configuration, the second coupling bracket to which a loadcorresponding to the seating sensor mechanism is not applied is moreeasily deformable than the first coupling bracket to which the loadcorresponding to the seating sensor mechanism is applied, and therefore,the first coupling bracket and the second coupling bracket upon impactabsorption can be deformed with a favorable balance.

Moreover, the above-described problem is solved by an embodiment of avehicle seat frame including a seat cushion frame, a seat back frame, afirst coupling bracket configured to couple a first cushion side frameas a side frame of the seat cushion frame on one side of the vehicleseat frame and a first seat back side frame as a side frame of the seatback frame on the one side, and a second coupling bracket configured tocouple a second cushion side frame as a side frame of the seat cushionframe on an other side of the vehicle seat frame and a second seat backside frame as a side frame of the seat back frame on the other side Aweak portion is provided at only one of the first or second couplingbracket. According to the above-described vehicle seat frame, thedeformability is differentiated between the right and left couplingbrackets coupling the seat cushion frame and the seat back frame, andtherefore, the amount of deformation of each of the right and leftcoupling brackets upon impact absorption can be adjusted.

According to the present disclosure, the deformability is differentiatedbetween the weak portions of the right and left coupling bracketscoupling the seat cushion frame and the seat back frame, and therefore,the amount of deformation of each of the right and left couplingbrackets upon impact absorption can be adjusted.

According to an embodiment of the present disclosure, the amount ofdeformation of each of the right and left coupling brackets upon impactabsorption can be adjusted according to the respective shapes of thefirst and second weak portions.

According to an embodiment of the present disclosure, each of the weakportions of the right and left coupling brackets is bent outward fromthe vehicle seat frame upon impact absorption so that the impact on theseat back frame can be reduced.

According to an embodiment of the present disclosure, the offset amountof each of the first and second weak portions is adjusted so that thedeformability of each weak portion can be controlled.

According to an embodiment of the present disclosure, the second weakportion provided at the second coupling bracket can be more easilydeformable upon impact absorption as compared to the first weak portionprovided at the first coupling bracket.

According to an embodiment of the present disclosure, in the case wherea stronger load is applied to the second coupling bracket than to thefirst coupling bracket upon rear collision, the balance in thedeformation amount between the second coupling bracket and the firstcoupling bracket can be achieved.

According to an embodiment of the present disclosure, the secondcoupling bracket to which a load of the main driving portion of theheight adjustment mechanism is not applied is more easily deformablethan the first coupling bracket to which the load of the main drivingportion of the height adjustment mechanism is applied, and therefore,the first coupling bracket and the second coupling bracket upon impactabsorption can be deformed with a favorable balance.

According to an embodiment of the present disclosure, the secondcoupling bracket to which the load corresponding to the seating sensormechanism is not applied is more easily deformable than the firstcoupling bracket to which the load corresponding to the seating sensormechanism is applied, and therefore, the first coupling bracket and thesecond coupling bracket upon impact absorption can be deformed with afavorable balance.

According to the present disclosure, the deformability is differentiatedbetween the weak portions of the right and left coupling bracketscoupling the seat cushion frame and the seat back frame, and therefore,the amount of deformation of each of the right and left couplingbrackets upon impact absorption can be adjusted.

BRIEF DESCRIPTION OF DRAWINGS

Various embodiments of the invention are illustrated in the drawings, inwhich:

FIG. 1 is a perspective view for describing a basic configuration of avehicle seat of a first embodiment;

FIG. 2 is a perspective view of a vehicle seat frame of the firstembodiment;

FIG. 3 is a side view for describing a height adjustment mechanism;

FIG. 4 is a perspective view for describing the height adjustmentmechanism;

FIG. 5 is a back view of the vehicle seat frame of the first embodiment;

FIGS. 6A and 6B are front and side views, respectively, of a couplingbracket configured to couple a frame provided with a main drivingportion of the height adjustment mechanism;

FIGS. 7A and 7B are front and side views, respectively, of a couplingbracket configured to couple a frame not provided with the main drivingportion of the height adjustment mechanism;

FIG. 8 is a perspective view of a vehicle seat frame of a secondembodiment;

FIG. 9 is a partial side view of an attachment portion of a seatingsensor;

FIG. 10 is a perspective view of a vehicle seat frame of a thirdembodiment; and

FIGS. 11A and 11B are front and side views of a coupling bracketconfigured to couple a frame provided with a main driving portion of aheight adjustment mechanism at the vehicle seat frame of the thirdembodiment.

DETAILED DESCRIPTION

A vehicle seat and a vehicle seat frame as a framework of the vehicleseat according to various embodiments of the present disclosure aredescribed below with reference to FIGS. 1 to 11.

The present embodiment relates to a vehicle seat frame including a seatcushion frame, a seat back frame, a first coupling bracket configured tocouple a first cushion side frame as a side frame of the seat cushionframe on one side of the vehicle seat frame and a first seat back sideframe as a side frame of the seat back frame on the one side, and asecond coupling bracket configured to couple a second cushion side frameas a side frame of the seat cushion frame on the other side of thevehicle seat frame and a second seat back side frame as a side frame ofthe seat back frame on the other side. A first weak portion provided atthe first coupling bracket and a second weak portion provided at thesecond coupling bracket are configured to have different deformabilityupon an impact absorpotion. Note that in the embodiments describedbelow, a case where the vehicle seat frame of the present disclosure isapplied as a vehicle seat frame is described as examples.

Note that in the description below, a “front-to-back direction” means afront-to-back direction when viewed from a person seated on the vehicleseat, and is a direction coincident with a vehicle traveling direction.A “seat width direction” means a transverse width direction of thevehicle seat, and is coincident with a right-to-left direction whenviewed from the person seated on the vehicle seat. Moreover, indescription below, a “left” indicates a left when viewed from the seatedperson, and similarly, a “right” indicates a right when viewed from theseated person. Further, a “height direction” means a height direction ofthe vehicle seat, and is coincident with an upper-to-lower directionwhen the vehicle seat is viewed from the front.

First, a basic configuration of a vehicle seat S of the presentembodiment is described based on FIG. 1. As illustrated in FIG. 1, thevehicle seat S has a seat back S1, a seat cushion S2, and a head restS3. Moreover, slide rail mechanisms 30, configured to slidably move aseat body (a main portion of the vehicle seat S) in the front-to-backdirection, are arranged at a lower portion of the seat cushion S2.Further, the vehicle seat S has, as a framework thereof, a vehicle seatframe F1 illustrated in FIG. 2. The vehicle seat frame F1 includes, asmain components, a seat back frame 10 and a seat cushion frame 20.

The seat back frame 10 has an inverted U-shaped upper frame 11, a seatback side frame 12L (equivalent to a first seat back side frame) forminga left end portion in the seat width direction, a seat back side frame12R (equivalent to a second seat back side frame) forming a right endportion in the seat width direction, and a lower member frame 13 thatbridges between lower end portions of the seat back side frame 12L andthe seat back side frame 12R. Moreover, a reclining shaft 14 of areclining mechanism is set between the lower end portions of the seatback side frame 12L and the seat back side frame 12R with the recliningshaft 14 penetrating the seat back side frame 12L and the seat back sideframe 12R.

The seat cushion frame 20 has an outer shape in a rectangular frameshape when viewed from above. The seat cushion frame 20 includes, asmain components, a cushion side frame 21R (equivalent to a first cushionside frame) positioned at a left end portion in the seat widthdirection, a cushion side frame 21L (equivalent to a second cushion sideframe) positioned at a right end portion in the seat width direction,and a pan frame 22 forming a front end portion of the seat cushion frame20. Moreover, an upper back end portion of the cushion side frame 21L isattached to the lower end portion of the seat back side frame 12Lthrough a coupling bracket 23L. Similarly, an upper back end portion ofthe cushion side frame 21R is attached to the lower end portion of theseat back side frame 12R through a coupling bracket 23R. Althoughdetails are described below, each of the coupling bracket 23L and thecoupling bracket 23R has a weak portion configured in a suitable shapesuch that the weak portion is easily deformable upon impact input. Forexample, the weak portions of the coupling bracket 23L and the couplingbracket 23R are crushed upon a rear collision of a vehicle in which thevehicle seat S is installed so that impact can be efficiently absorbed.

Further, as illustrated in FIG. 2, lower back end portions of thecushion side frame 21L and the cushion side frame 21R are coupledtogether through a member extending along the seat width direction. Thismember is a coupling pipe 24 as a hollow member, and specificallyincludes a round pipe. Moreover, both end portions of the coupling pipe24 in the seat width direction are supported by the cushion side frame21L and the cushion side frame 21R through an end sleeve 28L and an endsleeve 28R as tubular members.

In addition, a plurality of S-springs 25 as buttock support members areprovided between the cushion side frame 21L and the cushion side frame21R, the S-springs 25 being arranged in the seat width direction. EachS-spring 25 is provided for supporting the buttocks of a passenger asthe person seated on the vehicle seat S, and extends along thefront-to-back direction. Moreover, front end portions of the S-springs25 are fixed to an upper end surface of the pan frame 22. Further, backend portions of the S-springs 25 are fastened at the above-describedcoupling pipe 24 through engagement hooks 26 and an L-angled fixingbracket 27, the engagement hooks 26 and the fixing bracket 27 beingarranged between the cushion side frame 21L and the cushion side frame21R.

The vehicle seat S of the present embodiment includes a heightadjustment mechanism 40 configured to adjust the height of the seatcushion S2. The height adjustment mechanism 40 is disposed between theseat cushion frame 20 and an upper rail 32L of the slide rail mechanism30 in the upper-to-lower direction. When the passenger executes heightadjustment operation (e.g., the operation of pressing a not-shownup-and-down button), movable portions (for example, a main driving link41, a driven link 43, etc. as described below) of the height adjustmentmechanism 40 are operated. In this manner, the height of the seat bodyincluding the seat cushion S2 is adjusted.

A configuration of the height adjustment mechanism 40 of the presentembodiment is described below with reference to FIGS. 3 and 4. Asillustrated in FIGS. 3 and 4, the height adjustment mechanism 40 has themain driving link 41, a pinion gear 42, and the driven links 43, 44. Themain driving link 41 and the driven links 43, 44 swing together with theseat cushion S2 in the front-to-back direction and the upper-to-lowerdirection.

The main driving link 41 includes a metal plate member. Of the cushionside frame 21L and the cushion side frame 21R forming the seat cushionframe 20, the outer cushion side frame in the seat width direction (inthe present embodiment, the cushion side frame 21L) is disposed at aposition closer to the main driving link 41. Moreover, one end portionof the main driving link 41 in a longitudinal direction thereof is,through a pivot pin 41 b, swingably supported by a link support portion32 a positioned on an upper surface of the upper rail 32L. Further, theother end portion of the main driving link 41 in the longitudinaldirection has a substantially fan-shaped outer shape as illustrated inFIGS. 3 and 4. In addition, a front end portion of the substantiallyfan-shaped other end portion of the main driving link 41 in thelongitudinal direction has gear teeth. That is, the other end portion ofthe main driving link 41 in the longitudinal direction forms a sectorgear 41 a, and engages with the pinion gear 42 as illustrated in FIG. 3.The pinion gear 42 is rotatably attached to the cushion side frame 21Lprovided at the seat cushion frame 20. Moreover, the pinion gear 42 iscoupled to a drive motor attached to the cushion side frame 21L. Notethat a mechanism portion including the main driving link 41, the sectorgear 41 a, and the pinion gear 42 and configured to mainly operate theheight adjustment mechanism 40 is a main driving portion 40M, and amechanism portion configured to adjust the height of the seat inresponse to operation by the main driving portion 40M is a drivenportion.

The driven link 43 (equivalent to the driven portion of the heightadjustment mechanism 40) includes a metal plate member, and is a linkconfigured to swing in response to swinging operation of the maindriving link 41. The driven link 43 is supported to swing relative toeach of the cushion side frame 21L of the seat cushion frame 20 and theupper rail 32L. Specifically, one end portion of the driven link 43 in alongitudinal direction thereof is, as illustrated in FIG. 3, swingablysupported through a pivot pin 43 a by a link support portion 32 b placedon the upper surface of the upper rail 32L. Moreover, as illustrated inFIG. 3, the other end portion of the driven link 43 in the longitudinaldirection is swingably supported through a pivot pin 43 b by a lower endportion of the cushion side frame 21L.

Moreover, the driven link 44 (equivalent to the driven portion of theheight adjustment mechanism 40) is paired with the main driving link 41as illustrated in FIG. 4. Specifically, the main driving link 41 and thedriven link 44 are coupled together through the coupling pipe 24, theend sleeve 28L, and the end sleeve 28R. More specifically, one oflongitudinal end portions of the main driving link 41 provided with thesector gear 41 a has, at a back portion thereof, a semicircular cutoutportion 41 r. The end sleeve 28L is fitted in the cutout portion 41 rwith one end portion of the coupling pipe 24 in the seat width directionbeing fitted in the end sleeve 28L, and both of these components arefixed by welding. On the other hand, one of the longitudinal endportions of the driven link 44 supported by the cushion side frame 21Rhas, at a back portion thereof, a semicircular cutout portion 44 r. Theend sleeve 28R is fitted in the cutout portion 44 r with the other endportion of the coupling pipe 24 in the seat width direction being fittedin the end sleeve 28R, and both of these components are fixed bywelding.

Operation of the height adjustment mechanism 40 configured as describedabove is described. The passenger as the person seated on the seatexecutes the height adjustment operation (e.g., the operation ofpressing the not-shown up-and-down button), and accordingly, the drivemotor coupled to the pinion gear 42 is driven to rotate the pinion gear42. When the pinion gear 42 rotates, the position of engagement betweenthe pinion gear 42 and the sector gear 41 a changes. Accordingly, themain driving link 41 and the driven links 43, 44 swing. In this state,the end sleeves 28L, 28R welded to the main driving link 41 and thedriven link 44 and the coupling pipe 24 fitted in the end sleeves 28L,28R swing together. Thus, the cushion side frame 21L and the cushionside frame 21R of the seat cushion frame 20 rotate about the center ofrotation, i.e., the center axes of the coupling pipe 24, the end sleeve28L, and the end sleeve 28R, relative to the coupling pipe 24, the endsleeve 28L, and the end sleeve 28R. As a result, the seat cushion frame20 moves up and down, and therefore, the height of the seat body isadjusted.

FIG. 5 illustrates a back view of the vehicle seat frame F1 of the firstembodiment. The back view illustrated in FIG. 5 corresponds to a viewwhen the vehicle seat frame F1 is viewed from the back of the seat backframe 10. As illustrated in FIG. 5, the main driving portion 40M of theheight adjustment mechanism 40 is, in the vehicle seat frame F1,attached only to the cushion side frame 21L of the cushion side frames21L, 21R. For example, upon a rear collision, more impact load isapplied, increased by an impact load corresponding to the main drivingportion 40M, to the coupling bracket 23L attached to the cushion sideframe 21L as compared to an impact load applied to the coupling bracket23R attached to the cushion side frame 21R. Thus, if the couplingbracket 23L and the coupling bracket 23R are made of similar materialsin similar shapes with similar degrees of deformability, the amount ofdeformation of the coupling bracket 23L is greater than that of thecoupling bracket 23R, and therefore, there is a likelihood that thevehicle seat frame F1 does not equally deform in the right-to-leftdirection. For this reason, in the vehicle seat frame F1, mechanisms ofthe weak portions provided at the coupling bracket 23L and the couplingbracket 23R are differentiated from each other, and in this manner, thecoupling bracket 23L and the coupling bracket 23R are different fromeach other in deformability. Configurations of the coupling bracket 23Land the coupling bracket 23R are described below in detail withreference to FIGS. 6 and 7.

FIG. 6A illustrates a front view and FIG. 6B illustrates a side view ofthe coupling bracket 23L coupling the frame provided with the maindriving portion 40M of the height adjustment mechanism 40. Moreover,FIG. 7A illustrates a front view and FIG. 7B illustrates a side view ofthe coupling bracket 23R coupling the frame not provided with the maindriving portion 40M of the height adjustment mechanism 40.

As illustrated in FIG. 6A, the coupling bracket 23L has a shaftthrough-hole 231L for the reclining shaft 14 and with bolt fasteningholes 232L, 233L through each of which a bolt for fastening the cushionside frame 21L and the coupling bracket 23L together penetrates. Notethat the reclining mechanism is attached to the reclining shaft 14, andthe seat back frame 10 is coupled to the coupling bracket 23L throughthe reclining mechanism.

Moreover, as illustrated in FIGS. 6A and 6B, the coupling bracket 23Lhas a seat-back-side coupling region 235L (equivalent to a firstseat-back-side coupling region) forming a portion to be coupled to theseat back side frame 12L and including the shaft through-hole 231L, acushion-side coupling region 236L (equivalent to a first cushion-sidecoupling region) forming (a portion of) a portion to be coupled to thecushion side frame 21L and including the bolt fastening hole 233L, and aweak portion 237L (equivalent to a first weak portion) connecting theseat-back-side coupling region 235L and the cushion-side coupling region236L together and bent outward from the vehicle seat frame with respectto the seat-back-side coupling region 235L and the cushion-side couplingregion 236L.

As illustrated in FIG. 6B, an end surface of the seat-back-side couplingregion 235L in a seat inward direction (a seat inward direction in thecase of attaching the coupling bracket 23L to the vehicle seat frame F1)and an end surface of the cushion-side coupling region 236L in the seatinward direction are present within the same plane, and an offset amountindicating displacement of these end surfaces in the seat widthdirection is substantially zero. That is, the weak portion 237L is insuch a shape that a portion connected to the seat-back-side couplingregion 235L and a portion connected to the cushion-side coupling region236L are positioned within the substantially same plane in the seatwidth direction.

Next, as illustrated in FIG. 7A, the coupling bracket 23R has a shaftthrough-hole 231R for the reclining shaft 14 and with bolt fasteningholes 232R, 233R through each of which a bolt for fastening the cushionside frame 21R and the coupling bracket 23R together penetrates. Notethat the reclining mechanism is attached to the reclining shaft 14, andthe seat back frame 10 is coupled to the coupling bracket 23R throughthe reclining mechanism.

Moreover, as illustrated in FIGS. 7A and 7B, the coupling bracket 23Rhas a seat-back-side coupling region 235R (equivalent to a secondseat-back-side coupling region) forming a portion to be coupled to theseat back side frame 12R and including the shaft through-hole 231R, acushion-side coupling region 236R (equivalent to a second cushion-sidecoupling region) forming (a portion of) a portion to be coupled to thecushion side frame 21R and including the bolt fastening hole 233R, and aweak portion 237R (equivalent to a second weak portion) connecting theseat-back-side coupling region 235R and the cushion-side coupling region236R together and bent outward from the vehicle seat frame with respectto the seat-back-side coupling region 235R and the cushion-side couplingregion 236R.

As illustrated in FIG. 7B, an end surface of the seat-back-side couplingregion 235R in a seat inward direction (a seat inward direction in thecase of attaching the coupling bracket 23R to the vehicle seat frame F1)and an end surface of the cushion-side coupling region 236R in the seatinward direction are not present within the same plane, and an offsetamount indicating displacement of these end surfaces in the seat widthdirection is d (greater than zero). That is, the end surface of thecushion-side coupling region 236R is positioned inward of the seat withrespect to the end surface of the seat-back-side coupling region 235R.In other words, the weak portion 237R is in such a shape that a portionconnected to the cushion-side coupling region 236R is positioned inwardof the seat with respect to a portion connected to the seat-back-sidecoupling region 235R. Alternatively, the weak portion 237R may be insuch a shape that the portion connected to the cushion-side couplingregion 236R is positioned outward from the vehicle seat frame withrespect to the portion connected to the seat-back-side coupling region235R.

As described above, the offset amount of the coupling bracket 23R is setgreater than that of the coupling bracket 23L, and therefore, thecoupling bracket 23R (the weak portion 237R) is more easily deformableas compared to the coupling bracket 23L (the weak portion 237L). Inother words, the offset amount of the coupling bracket 23R is setgreater than that of the coupling bracket 23L, and therefore, thecoupling bracket 23L is less deformable as compared to the couplingbracket 23R. As described above, the coupling bracket 23L is formed tobe less deformable than the coupling bracket 23R by an impact loadcorresponding to the main driving portion 40M, and therefore, adjustmentcan be made such that a deformation amount becomes equal between thecoupling bracket 23L and the coupling bracket 23R.

Next, a vehicle seat frame F2 of a second embodiment of the presentdisclosure is described with reference to FIGS. 8 and 9. The vehicleseat frame F2 of the second embodiment is different from the vehicleseat frame F1 of the first embodiment in that not a height adjustmentmechanism 40 but a seating sensor mechanism 50 configured to detectwhether a passenger is seated is provided between a cushion side frame21L and an upper rail 32L, but is the same as the vehicle seat frame F1on other points. Differences are mainly described below.

FIG. 8 illustrates a perspective view of the vehicle seat frame F2 ofthe second embodiment, and FIG. 9 illustrates a partial side view of anattachment portion of the seating sensor mechanism 50.

In the vehicle seat frame F2 of the second embodiment, the seatingsensor mechanism 50 is provided only at an outer one (in the presentembodiment, the cushion side frame 21L) of the cushion side frame 21Land a cushion side frame 21R in the seat width direction, the cushionside frame 21L and the cushion side frame 21R forming a seat cushionframe 20.

As illustrated in FIGS. 8 and 9, the seating sensor mechanism 50includes a seat position sensor 50A provided at a seat front portion,and a seat weight sensor 50B provided at a seat back portion. Asillustrated in FIG. 9, an upper portion of the seat position sensor 50Ais attached to the cushion side frame 21L through a bracket 51A, and alower portion of the seat position sensor 50A is provided in contactwith the upper rail 32L. Note that the position of the passenger in theseat front-to-back direction can be detected by the seat position sensor50A.

Moreover, as illustrated in FIG. 9, an upper portion of the seat weightsensor 50B is attached to the cushion side frame 21L through a bracket51B, and a lower portion of the seat weight sensor 50B is provided incontact with the upper rail 32L. Note that the weight of an objectloaded on a seat and the position of the center of gravity of the objectloaded on the seat can be detected by the seat weight sensor 50B.

As described above, in the vehicle seat frame F2 of the secondembodiment, the seating sensor mechanism 50 is attached only to thecushion side frame 21L of the cushion side frames 21L, 21R. Upon a rearcollision, more impact load is applied, increased by an impact loadcorresponding to the seating sensor mechanism 50, to a coupling bracket23L coupled to the cushion side frame 21L as compared to an impact loadapplied to coupling bracket 23R attached to the cushion side frame 21R.For this reason, the configurations of the coupling bracket 23L and thecoupling bracket 23R as illustrated in FIGS. 6 and 7 are also employedfor the vehicle seat frame F2 so that the coupling bracket 23R (a weakportion 237R) is more easily deformable as compared to the couplingbracket 23L (a weak portion 237L). Thus, in the vehicle seat frame F2,adjustment can be made such that a deformation amount becomes equalbetween the coupling bracket 23L and the coupling bracket 23R.

Next, a vehicle seat frame F3 of a third embodiment of the presentdisclosure is described with reference to FIGS. 10, 11A, and 11B. Thevehicle seat frame F3 of the third embodiment is different from thevehicle seat frame F1 of the first embodiment in that a cushion sideframe 21L and a seat back side frame 12L are coupled together through acoupling bracket 123L that is not provided with a weak portion, but isthe same as the vehicle seat frame F1 on other points. Differences aremainly described below.

FIG. 10 illustrates a perspective view of the vehicle seat frame F3 ofthe third embodiment. FIG. 11A illustrates a front view and FIG. 11Billustrates a side view of the coupling bracket 123L coupling a frameprovided with a main driving portion 40M of a height adjustmentmechanism 40.

As illustrated in FIG. 10, in the vehicle seat frame F3 of the thirdembodiment, an upper back end portion of the cushion side frame 21L isattached to a lower end portion of a seat back side frame 12L throughthe coupling bracket 123L.

Moreover, as illustrated in FIG. 11A, the coupling bracket 123L has ashaft through-hole 124L for a reclining shaft 14 and bolt fasteningholes 125L, 126L, through each of which a bolt penetrates for fasteningthe cushion side frame 21L and the coupling bracket 123L together. Notethat a reclining mechanism is attached to a reclining shaft 14, and aseat back frame 10 is coupled to the coupling bracket 123L through thereclining mechanism.

Note that as illustrated in FIGS. 11A and 11B, the coupling bracket 123Lis not provided with a weak portion in such a shape that the weakportion is easily deformable upon impact input. That is, no portion bentoutward from the vehicle seat frame is, unlike the coupling bracket 23L,provided between the shaft through-hole 124L and the bolt fastening hole126L at the coupling bracket 123L. On the other hand, a coupling bracket23R has a weak portion 237R as illustrated in FIGS. 7A and 7B, andtherefore, the coupling bracket 23R (the weak portion 237R) can be moreeasily deformable as compared to the coupling bracket 123L. With thisconfiguration, even in a case where more impact load is applied, e.g.,increased by an impact load corresponding to the main driving portion40M of the height adjustment mechanism 40, to the coupling bracket 123Lattached to the cushion side frame 21L as compared to the couplingbracket 23R attached to a cushion side frame 21R, adjustment can be madesuch that a deformation amount becomes equal between the couplingbracket 123L and the coupling bracket 23R. Note that the shape of theweak portion 237R of the coupling bracket 23R in the third embodiment isnot limited to the shape illustrated in FIG. 7. For example, the weakportion 237R may be in such a shape that an offset amount issubstantially zero as in the coupling bracket 23L illustrated in FIG. 6or in other shapes.

The examples of the vehicle seat frame to which the present disclosureis applied have been mainly described above, but the present disclosureis also similarly applicable to other vehicle seats for ships,airplanes, etc. Moreover, the above-described embodiments have been setforth merely as examples for the sake of easy understanding of thepresent disclosure, and are not intended to limit the presentdisclosure. Changes and modifications can be made to the presentdisclosure without departing from the gist of the present disclosure,and needless to say, the present disclosure includes equivalentsthereof.

For example, the weak portion provided at the coupling bracket is notlimited to the form in which a portion of the coupling bracket is bentoutward from the vehicle seat frame. For example, in the couplingbracket, the weak portion may be formed in such a manner that thestrength of a metal structure of a portion forming the weak portion isdecreased relative to the strength of portions forming other portionsthan the weak portion, or may be formed in such a manner that a bead forinducing bending is provided at the coupling bracket.

Moreover, in the above-described embodiments, the example where the maindriving portion 40M of the height adjustment mechanism 40 or the seatingsensor mechanism 50 is provided at the left frame has been described asan example, but the main driving portion 40M of the height adjustmentmechanism 40 or the seating sensor mechanism 50 may be provided at theright frame. In this case, the coupling bracket coupling the right framemay be configured to be less deformable upon a rear collision ascompared to the coupling bracket coupling the left frame (e.g., theoffset amount of the coupling bracket coupling the right frame isdecreased than that of the coupling bracket coupling the left frame).

TABLE OF REFERENCE NUMERALS 10: seat back frame 11: upper frame 12L,12R: seat back side frame 13: lower member frame 14: reclining shaft 16:upper cross member 20: seat cushion frame 21L, 21R: cushion side frame22: pan frame 23L, 23R, 123L: coupling bracket 24: coupling pipe 25:S-spring 26: engagement hook 27: fixing bracket 28L, 28R: end sleeve 30:slide rail mechanism 32L: upper rail 32a, 32b: link support portion 40:height adjustment mechanism 40M: main driving portion 41: main drivinglink 41a: sector gear 41b, 43a, 43b: pivot pin 41r, 44r: cutout portion42: pinion gear 43, 44: driven link 50: seating sensor mechanism 50A:seat position sensor 50B: seat weight sensor 51A, 51B: bracket 124L,231L, 231R: shaft through-hole 125L, 126L, 232L, 232R, 233L, 233R: boltfastening hole 235L, 235R: seat-back-side coupling region 236L, 236R:cushion-side coupling region 237L, 237R: weak portion F1, F2, F3:vehicle seat frame S: vehicle seat S1: seat back S2: seat cushion S3:head rest

The invention claimed is:
 1. A vehicle seat frame comprising: a seatcushion frame; a seat back frame; a first coupling bracket configured tocouple a first cushion side frame as a side frame of the seat cushionframe on one side of the vehicle seat frame and a first seat back sideframe as a side frame of the seat back frame on the one side; and asecond coupling bracket configured to couple a second cushion side frameas a side frame of the seat cushion frame on an other side of thevehicle seat frame and a second seat back side frame as a side frame ofthe seat back frame on the other side; wherein the first couplingbracket includes a first seat-back-side coupling region having a portionto be coupled to the first seat back side frame, a first cushion-sidecoupling region having a portion to be coupled to the first cushion sideframe, and a first weak portion that connects the first seat-back-sidecoupling region and the first cushion-side coupling region together;wherein the second coupling bracket includes a second seat-back-sidecoupling region having a portion to be coupled to the second seat backside frame, a second cushion-side coupling region having a portion to becoupled to the second cushion side frame, and a second weak portion thatconnects the second seat-back-side coupling region and the secondcushion-side coupling region together; and wherein an offset amount in aseat width direction between a surface forming the first seat-back-sidecoupling region and a surface forming the first cushion-side couplingregion at the first coupling bracket is different from an offset amountin the seat width direction between a surface forming the secondseat-back-side coupling region and a surface forming the secondcushion-side coupling region at the second coupling bracket.
 2. Thevehicle seat frame of claim 1, wherein the first weak portion and thesecond weak portion are different from each other in their respectiveshapes.
 3. The vehicle seat frame of claim 1, wherein: the first weakportion is bent outward from the vehicle seat frame with respect to thefirst seat-back-side coupling region and the first cushion-side couplingregion; and the second weak portion is bent outward from the vehicleseat frame with respect to the second seat-back-side coupling region andthe second cushion-side coupling region.
 4. The vehicle seat frame ofclaim 1, wherein the surface forming the first seat-back-side couplingregion and the surface forming the first cushion-side coupling regionare positioned within a same plane, and the surface forming the secondcushion-side coupling region is positioned inward or outward of thevehicle seat frame with respect to the surface forming the secondseat-back-side coupling region.
 5. The vehicle seat frame of claim 1,wherein the second weak portion is formed to be more easily deformableupon impact absorption as compared to the first weak portion.
 6. Thevehicle seat frame of claim 4, wherein a main driving portion of aheight adjustment mechanism configured to adjust a height of the seat isprovided only at the first cushion side frame of the first and secondcushion side frames.
 7. The vehicle seat frame of claim 4, wherein aseating sensor mechanism configured to detect seating of a passenger isprovided only at the first cushion side frame of the first and secondcushion side frames.
 8. The vehicle seat frame of claim 3, whereindeformability upon impact absorption is different between the first weakportion of the first coupling bracket and the second weak portion of atthe second coupling bracket.
 9. A vehicle seat, comprising the vehicleseat frame according to claim 1.